I am going to build a A-frame swing set with 4x4s and am wondering about one thing. When I read most of the tutorials, the swing set sits directly on the ground. Is it ok for the water introsuion? Even if the lumbers are rot-resistent, I know that, for deck building or shed building, it is advised that the structure is off the ground with the piers or the posts are buried, being surrounded by the cement.
Because it is related to the safety issue, I thought I might need to clarify this before taking an action.